(i) Technical Field
The present invention relates to a folded portion flattening device built in a post treatment apparatus which executes a variety of post treatments on a sheet in which an image is formed with an image forming apparatus, the post treatment apparatus and the image forming apparatus.
(ii) Related Art
Recently, image forming apparatuses have been often used on line and post treatment apparatuses for executing a variety of post treatments such as stapling, binding and punching on a sheet in which an image is formed have been widely used.
For example, FIG. 1 shows an image forming apparatus 1 such as electrophotographic printer, copying machine and a post treatment apparatus 2 for executing a variety of post treatments on a sheet in which an image is formed with the image forming apparatus 1, connected to this image forming apparatus 1. This post treatment apparatus 2 includes, for example, a transport unit 3 for receiving a sheet from the image forming apparatus 1, an intermediate treatment unit 4 for executing intermediate treatment such as folding, stapling, binding, interposing upon a sheet received by this transport unit 3, and a final treatment unit 5 for executing a variety of final treatments upon the sheet sent from the intermediate treatment unit 4.
The final treatment unit 5 includes, for example, a cutting section 6 for cutting out irregular portion at the rear end of a booklet folded in two, a folded portion flattening section 7 for flattening a curve of the folded portion at the front end of the booklet after cut, a punching treatment section 8 for punching near the front end of the booklet after flattened and a stacker section 9 in which the punched booklets are stacked.
When a booklet 10 folded in two by the intermediate treatment unit 4 is sent into the cutting section 6 of the final treatment portion with a folded portion 10a ahead as shown in FIG. 2, an irregular portion 10b at the rear end of the booklet 10 is cutout by a movable blade 6a and a fixed blade 6b of Guillotine cutter, a pressing type cutter which drops in the direction of an arrow, as shown in FIG. 2(b).